Expandable band and locking mechanism

ABSTRACT

The expandable band is used to secure a sealing element within a generally cylindrical structure, such as a pipe or manhole, or other round hole. The expandable band includes a band body having a first band end portion and a second band end portion. A plurality of slots are disposed in the first band end portion, and a locking member extends from the second band end portion. The locking member includes a tab for extending through the second band end portion and into one of the plurality of slots to lock the expandable band at the desired diameter. An end section of the second band end portion extends beyond the tab of the locking member to ease the transition between the overlapping first and second band end portions. When the band is expanded, the tab is disengaged from the slots and slides over the slots, allowing the first and second band end portions to move relative to one another. At the desired diameter, the tab engages one of the slots to lock the band at the desired diameter. The locking member is disposed on the outside region of the band with the tab extending inward such that the sealing member provides a resilient backing against the locking member.

FIELD OF THE INVENTION

The present invention relates to expandable bands and locking mechanismsfor such bands and more particularly, to an expandable band having slotsat one end and a locking tab at the other end to engage one of the slotsand lock the band at the desired diameter.

BACKGROUND OF THE INVENTION

Expandable bands are commonly used to secure flexible sealing elementsor gaskets against an internal surface of a pipe, manhole, or othersimilar structure. Expandable bands typically fit against an annularsurface within the sealing element and are expanded to apply pressureagainst the sealing element. Various types of locking mechanisms areused to lock the band into the expanded position against the sealingelement.

The existing bands and locking mechanisms, however, have a number oflimitations and disadvantages. Many of the existing expandable bands areexpandable to only one diameter and therefore have a limited overallexpansion range. Many of these bands also require a number of steps toboth expand and lock the band and are not capable of quickly andsecurely locking the band over a range of diameters. Moreover, theexisting expandable bands are difficult to release or "unlock" andcannot easily be removed or adjusted to a smaller diameter. Otherexisting bands do not slide easily or bind being installed or adjusted.Overall, the existing bands are not useful with seals of various sizesthat need to be installed in pipes or manholes having various sizes.

Accordingly, a need exists for an expandable band that is easilyinstalled, adjusted and securely locks over a range of diameters. A needalso exists for an expandable band that is more easily released from alocking position.

SUMMARY OF THE INVENTION

The present invention features an expandable band comprising a band bodyhaving a first band end portion and a second band end portion. Aplurality of slots are disposed in the first band end portion of theband body. A locking member is disposed on the second band end portionand includes a tab for extending through an aperture in the second bandend portion and into one of the plurality of slots to lock theexpandable band at a desired diameter. The second band end portion ofthe band body includes an end section that extends beyond the tab of thelocking member.

The first and second band end portions of the band body preferablyoverlap to form a generally annular shape with the second band endportion having the locking member disposed on an outside region of theband. The tab of the locking member preferably extends inwardly withrespect to the band to engage one of the plurality of slots and forms anobtuse angle with respect to a plane tangential to the second band endportion of the band body.

The preferred embodiment of the band b has a generally U-shapedcross-section such that the band body includes a base portion and sideportions extending from the base portion. The plurality of slots aredisposed in the base portion of the band body. At least part of thefirst and second band end portions also preferably have a generallyU-shaped cross-section, and the first band end portion has a narrowerwidth than the second band end portion such that the first band endportion fits within the U-shaped cross-section of the second band endportion. In the preferred embodiment, the second band end portion hasthe U-shaped cross-section on each side of the tab.

The end section of the second band end portion also preferably has aflat cross-section extending from and one-piece with the section of thesecond end portion having the U-shaped cross-section. Alternatively, thesecond band end portion can include a separate extension member havingthe flat cross-section and attached to the section of the second bandend portion having the U-shaped cross-section.

In one embodiment, the first band end portion having the plurality ofslots is one piece with the band body. In another embodiment, the firstband end portion includes a separate piece attached to the band body andhaving the plurality of slots. In one embodiment, the locking memberincludes a semi-rigid strip attached to the second band end portion.

The preferred embodiment of the expandable band further includes anengaging element disposed on an inside surface of the band body, forengaging with a band expansive mechanism. In one example, the engagingelement includes a block attached to the inside surface of the bandbody.

The present invention also features a sealing system comprising aresilient sealing member for sealing an internal surface of acylindrical structure and one or more expandable bands.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reading the following detailed description, takentogether with the drawings wherein:

FIG. 1 is a partial cross-sectional side view of an expandable band,according to the present invention, installed within a sealing element;

FIG. 2 is a bottom plan view of overlapping first and second endportions of the expandable band, according to the present invention;

FIG. 3 is a bottom plan view of a first end portion of the expandableband, according to an alternative embodiment of the present invention;

FIG. 4 is a cross-sectional view of the expandable band of the presentinvention taken along line 4--4 in FIG. 2;

FIG. 5 is a top plan view of the second end portion of the expandableband, according to the present invention;

FIG. 5A is a top plan view of the second end portion of the expandableband, according to another embodiment of the present invention;

FIG. 6 is a bottom plan view of the second end portion of the expandableband, according to the present invention;

FIG. 7 is a cross-sectional view of the second end portion of theexpandable band, according to the present invention, taken along line7--7 in FIG. 5;

FIG. 8 is a schematic view of the expandable band and an expansionmechanism used to expand the expandable band, according to the exemplaryembodiment of the present invention;

FIG. 8A is a cross-sectional view of the expandable band beingdisengaged with a tool, according to one method of the presentinvention;

FIG. 9 is a cross-sectional view of the overlapping first and secondband end portions as the expandable band is being expanded, according tothe present invention; and

FIG. 10 is a cross-sectional view of the overlapping first and secondband end portions of the expandable band in a locked position, accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An expandable band 10, FIG. 1, according to the present invention, isused to secure a sealing element 2, such as a rubber seal or gasket, inthe interior of a round structure 4, such as a pipe or manhole, or around hole through the wall of a structure. The expandable band 10expands outwardly to secure the sealing element 2 against the internalsurface of the cylindrical structure 4. The expandable band 10 locks inthe desired expanded position within a range of diameters, as will bedescribed in detail below. Although the exemplary embodiment shows asealing element 2 and cylindrical structure 4, the present inventioncontemplates various other uses for the expandable band 10 with othertypes of structures of different shapes.

The expandable band 10 generally includes a band body 12 having a firstband end portion 14 and a second band end portion 16. The first andsecond end portions 14, 16 of the band body 12 preferably overlap toform a generally annular shaped band. In one example, the band body 12has a generally U-shaped cross-section and is made of 304 or 316stainless steel or any other suitable material. When the band isexpanded, the first and second band end portions 14, 16 move in oppositedirections as shown by the direction of arrows 18, 20 respectively.

According to the preferred embodiment, a plurality of slots 22, FIG. 2,are stamped, milled, or otherwise disposed in the first band end portion14. In one example, the slots 22 have a generally rectangular shape witha radius at each end and preferably have a width of about 0.125 in., alength of about 0.688 in. and a spacing of about 0.281 in. The presentinvention contemplates other shapes and sizes for the slots 22.

A locking member (or latch) 24 (FIG. 1) is disposed at the second bandend portion 16 and includes a tab 26 that extends through an aperture inthe second band end portion 14 into one of the slots 22 to lock theexpandable band 10 at the desired diameter. In the preferred embodiment,the second band end portion 16 overlaps the first band end portion 14such that the tab 26 extends generally inwardly with respect to the band10 (FIG. 1) to engage one of the slots 22. The second band end portion16 also preferably includes an end section 28 that extends to a pointbeyond the tab 26 of the locking member 24 to ease the transition at thesecond end portion 14 where the second end portion 14 overlaps the firstend portion 16.

In one embodiment, the first band end portion 14 is one piece with theband body 12 (FIG. 2). In another embodiment, the first band end portion14, FIG. 3, is a separate piece 30 attached to the band body 12, forexample, by welding.

According to the exemplary embodiment, at least part of the first andsecond band end portions 14, 16, FIG. 4, also have a generally U-shapedcross-section. The first band end portion 14 includes a base portion 32and side portions 34, 36 extending from the base portion 32 to form theU-shaped cross section. The plurality of slots 22 are disposed in thebase portion 32. The first band end portion 14 preferably has a narrowerwidth than the second band end portion 16 such that the first band endportion 14 fits (or nests) within the U-shaped cross-section of thesecond band end portion 16. In the embodiment of FIG. 2, the first bandend portion 14 is "necked down" from the band body 12 to form thenarrower width. In the embodiment of FIG. 3, the separate piece 30attached to the band body 12 to form the first band end portion 14 hasthe narrower width. Alternatively, the present invention contemplatesvarious types of cross-sections for the band body 12 and first andsecond band end portions 14, 16 including, but not limited to, aC-shaped cross-section, a corrugated cross-section, and a flatcross-section.

The locking member 24, FIGS. 5-7, according to the exemplary embodimentof the present invention, includes a semi-rigid strip 40 attached at oneend to the second band end portion 16, for example, by welding. The tab26 extends from the other end of the semi-rigid strip 40 and preferablyforms an obtuse angle a with respect to a plane 41 tangential to thesecond band end portion 16. The aperture 42 is cut out from the secondband end portion 16 to receive the tab 26. The preferred material forthe semi-rigid strip 40 is hard and strong like stainless steel andallows for a 60-90 degree bend. The semi-rigid strip 40 forming thelocking mechanism is preferably about 0.074 in. thick, 0.5 in. wide, and3.75 in. long. The present invention contemplates other suitablematerials, shapes and sizes for the locking mechanism 24 as well asother ways of attaching the locking mechanism 24 to the second band endportion 16.

The second band end portion 16 preferably has a section 44 with aU-shaped cross section extending just beyond the tab 26. The end section28 of the second band end portion 16 extends from and is one piece withthe U-shaped section 44 of the second band end portion 16 and preferablyhas a generally flat cross-section. Alternatively, the end section 28(FIG. 5A) can be formed by a separate extension member 46 made of asemi-rigid material, such as the material of the band, and attached atone end to the second band end portion 16, for example, by welding. Theseparate extension member 46 has a cut out region 47 that receives thelocking member 24 and forms the aperture through which the tab 26extends. The extension member 46 extends beyond the tab 26 to ease thetransition where the first and second band end portions 14, 16 overlap.

The expandable band 10, FIG. 8, further includes an engaging element 50,such as a block, attached to an inside surface 52 of the band body 12.According to one method of use, a band expansion mechanism 54 is used toexpand the expandable band 10. Expanding members 56, 58 of the expansionmechanism 54 are engaged with the engaging element 50 and an end face 60of the first band end portion 14 to cause the first and second band endportions 14, 16 to move in the direction of arrows 18, 20. The presentinvention also contemplates other types of engaging elements 50, such asa hole or aperture in the band body 12. The present invention furthercontemplates other types of band expansion mechanisms.

As the band is expanded, the deformability of sealing element 2 allowsthe tab 26, FIG. 9, to be disengaged from the slots 22 in the first bandend portion 14, allowing the first and second band end portions 14, 16to easily slide relative to one another in the directions of arrows 18,20 without the necessity of first band end portion having to "lift" outof engagement with tab 26. When the desired diameter of expansion isreached, the tab 26, FIG. 10, will engage the slot 22a at the desireddiameter, thereby locking the band 10 by preventing relative movementbetween the first and second band end portions 14, 16. The angle α ofthe tab 26 allows the tab 26 to easily slide out of engagement with theslots 22 when the band 10 is expanded and facilitates locking of the tabwithin the slot 22a.

The pressure applied by the sealing element 2 against the locking member24 holds the tab 26 in the slot 22a. By having the locking member 24disposed on an outside region of the band against sealing element 2 withthe tab 26 facing generally inwardly, the sealing element 2 provides aresilient or spring-loaded backing for the tab 26. This resilientbacking allows the end portions 14, 16 of the band 10 to slide easilywithout binding.

According to one method of disengaging the band, a tool 62, FIG. 8A,similar to a screw driver is used. A flat head 64 of the tool 62 isinserted into the gap 66 forward of the tab 26 (FIG. 8) and between thefirst and second band end portions 14, 16, for example, between thesides that form the U-shaped cross section. The tool is then pivotedgenerally in the direction of arrow 68 such that the flat head 64 liftsthe inner, first band end portion 14 away from the outer, second bandend portion 16 until the tab is released from engagement with the slot22a. If necessary, additional impact force can be applied to the tool62, for example, with a hammer.

Accordingly, the expandable band of the present invention is capable ofexpanding to and effectively locking at a wider range of diameters. Theexpandable band of the present invention also facilitates thedisengagement of the band for removal as well as the installation andadjustment of the band.

Modifications and substitutions by one of ordinary skill in the art areconsidered to be within the scope of the present invention which is notto be limited except by the claims which follow.

What is claimed is:
 1. An expandable band comprising:a band body havinga first band end portion and a second band end portion, wherein saidfirst band end portion and said second band end portion overlap to forma generally annular shape; a plurality of sequential slots disposed insaid first band end portion of said band body; a locking member disposedon an outer region of said band body at said second band end portion ofsaid band body, said locking member including a tab for extendingthrough an aperture in said second band end portion and into one of saidplurality of sequential slots to lock said expandable band at a desireddiameter, wherein said expandable band is capable of expanding to andlocking into a plurality of diameters; and wherein said second band endportion of said band body includes an end section extending beyond saidtab of said locking member.
 2. The expandable band of claim 1 whereinsaid band body has a generally U-shaped cross section.
 3. The expandableband of claim 2 wherein said first and second band end portions of saidband body have said generally U-shaped cross section, and wherein saidfirst band end portion of said band body has a narrower width than saidsecond band end portion such that said first band end portion fitswithin said U-shaped cross section of said second band end portion. 4.The expandable band of claim 1 wherein at least said second band endportion of said band body has a generally U-shaped cross section, andwherein said first band end portion of said band body has a narrowerwidth than said second band end portion such that said first band endportion fits within said U-shaped cross section of said second band endportion.
 5. The expandable band of claim 1 wherein said band bodyincludes a base portion and side portions extending from said baseportion, and wherein said plurality of slots are disposed in said baseportion of said band body.
 6. The expandable band of claim 1 whereinsaid second band end portion having said locking member is disposed onan outside region of the band, and wherein said tab of said lockingmember extends inwardly with respect to said band to engage said one ofsaid plurality of slots.
 7. The expandable band of claim 1 wherein saidfirst band end portion includes a separate piece attached to said bandbody and having said plurality of slots.
 8. The expandable band of claim1 wherein said tab forms an obtuse angle with respect to a planetangential to said second band end portion of said band body.
 9. Theexpandable band of claim 1 wherein said locking member includes asemi-rigid strip having said tab and attached to said second band endportion of said band body.
 10. The expandable band of claim 1 whereinsaid second band end portion includes a section having a U-shapedcross-section, and wherein said end section of said second band endportion extends as one piece from said section of said band body havingsaid U-shaped cross-section.
 11. The expandable band of claim 1 whereinsaid end section of said second band end portion includes a separateextension member attached to said second band end portion of said bandbody, wherein said separate extension member has a cut out regionforming said aperture through said second band end portion for receivingsaid tab.
 12. The expandable band of claim 1 further including anengaging element disposed on an inside surface of said band body, forengaging with a band expansion mechanism.
 13. The expandable band ofclaim 12 wherein said engaging element includes a block attached to saidinside surface of said band body.
 14. A sealing system comprising:aresilient sealing member for sealing an internal surface of acylindrical member; and an expandable band comprising:a band body havinga first end and a second end, wherein said first end and said second endoverlap to form a generally annular shape such that said expandable bandcontacts said resilient sealing member; a plurality of sequential slotsdisposed in said band body proximate said first end; a locking memberextending from said band body proximate said second end, said lockingmember including a tab for extending through said second band endportion and into one of said plurality of sequential slots to lock saidexpandable band at a desired diameter, wherein said expandable band iscapable of expanding to and locking into a plurality of diametersagainst said resilient sealing member, wherein said locking member isdisposed on an outer region of said band body and said tab extendsinwardly such that said resilient sealing member provides a resilientbacking for said locking member; and wherein said second band endportion of said band body includes an end section extending beyond saidtab of said locking member.
 15. The sealing system of claim 14 whereinsaid band body has a generally U-shaped cross section.
 16. The sealingsystem of claim 15 wherein said first and second band end portions ofsaid band body have said generally U-shaped cross section, and whereinsaid first band end portion of said band body has a narrower width thansaid second band end portion such that said first band end portion fitswithin said U-shaped cross section of said second band end portion. 17.The sealing system of claim 16 wherein said end section of said secondband end portion has a generally flat cross-section and extends as onepiece from a section of said second band end portion having a generallyU-shaped cross section.
 18. The sealing system of claim 14 wherein saidlocking member includes a semi-rigid strip having said tab and attachedto said second band end portion of said band body.